Fix the jsonbChangePayloadSize() routine so that it shifts the payload in order

to always render the most compact encoding of the payload size.  This is
necessary as sometimes (as discovered by dbsqlfuzz) the payload size can
grow significantly due to json_insert() or json_replace().

FossilOrigin-Name: 8d6d04ca975ec55c419d40d8463c433b0db698c9fb4812ab9f16d4ee5bee460e

manifest

@@ -1,5 +1,5 @@
-C Improvements\sto\serror\smessages\sreturned\swhen\sthe\s->>\soperator\sfails.
+C Fix\sthe\sjsonbChangePayloadSize()\sroutine\sso\sthat\sit\sshifts\sthe\spayload\sin\sorder\nto\salways\srender\sthe\smost\scompact\sencoding\sof\sthe\spayload\ssize.\s\sThis\sis\nnecessary\sas\ssometimes\s(as\sdiscovered\sby\sdbsqlfuzz)\sthe\spayload\ssize\scan\ngrow\ssignificantly\sdue\sto\sjson_insert()\sor\sjson_replace().
-D 2023-10-07T17:50:06.014
+D 2023-10-07T19:05:10.497
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -670,7 +670,7 @@ F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h f9c2dfb84dce7acf95ce6d289e46f5f9d3d1afd328e53da8f8e9008e3b3caae6
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
 F src/insert.c 3f0a94082d978bbdd33c38fefea15346c6c6bffb70bc645a71dc0f1f87dd3276
-F src/json.c a5d273004e0b0d4b961efe59b403c5b118218b3db2c2d61b4512ea2815ada8b2
+F src/json.c f526f060002c245769018dc5610bb64c981fb41b239b4d21781c47c6f6e83f1c
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 98cfba10989b3da6f1807ad42444017742db7f100a54f1032af7a8b1295912c0
 F src/main.c 618aeb399e993cf561864f4b0cf6a331ee4f355cf663635f8d9da3193a46aa40
@@ -2124,8 +2124,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 358de1b09f3d5ec0fe459775b0a2a99dfa235817327016b472aaa1ed56d952e6
+P 2f3388f14c843f1c02926e8b929365c06c1f1f4ea6fe6316092c3799c14549d3
-R 65b1837fdcd2785b2dbe03dd6bcb09bb
+R 9d37d6a70144b585d8728dd14898ad5e
 U drh
-Z f25f60a6b37a3fc4a80bb7878104ebfa
+Z 1ec73fd9ef6d1fd16b94f82c874a9e54
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-2f3388f14c843f1c02926e8b929365c06c1f1f4ea6fe6316092c3799c14549d3
+8d6d04ca975ec55c419d40d8463c433b0db698c9fb4812ab9f16d4ee5bee460e

src/json.c

@@ -2607,24 +2607,55 @@ static void jsonBlobChangePayloadSize(
 ){
   u8 *a;
   u8 szType;
+  u8 nExtra;
+  u8 nNeeded;
+  i8 delta;
   if( pParse->oom ) return;
   a = &pParse->aBlob[i];
   szType = a[0]>>4;
   if( szType<=11 ){
-    assert( szPayload<=11 );
+    nExtra = 0;
+  }else if( szType==12 ){
+    nExtra = 1;
+  }else if( szType==13 ){
+    nExtra = 2;
+  }else{
+    nExtra = 4;
+  }
+  if( szPayload<=11 ){
+    nNeeded = 0;
+  }else if( szPayload<=0xff ){
+    nNeeded = 1;
+  }else if( szPayload<=0xffff ){
+    nNeeded = 2;
+  }else{
+    nNeeded = 4;
+  }
+  delta = nNeeded - nExtra;
+  if( delta ){
+    u32 newSize = pParse->nBlob + delta;
+    if( delta>0 ){
+      if( newSize>pParse->nBlobAlloc && jsonBlobExpand(pParse, newSize) ){
+        return;  /* OOM error.  Error state recorded in pParse->oom. */
+      }
+      a = &pParse->aBlob[i];
+      memmove(&a[1+delta], &a[1], pParse->nBlob - (i+1));
+    }else{
+      memmove(&a[1], &a[1-delta], pParse->nBlob - (i+1-delta));
+    }
+    pParse->nBlob = newSize;
+  }
+  if( nNeeded==0 ){
     a[0] = (a[0] & 0x0f) | (szPayload<<4);
-  }else if( szType==0xc ){
+  }else if( nNeeded==1 ){
-    assert( szPayload<=0xff );
+    a[0] = (a[0] & 0x0f) | 0xc0;
-    assert( i+1<pParse->nBlob );
     a[1] = szPayload & 0xff;
-  }else if( szType==0xd ){
+  }else if( nNeeded==2 ){
-    assert( szPayload<=0xffff );
+    a[0] = (a[0] & 0x0f) | 0xd0;
-    assert( i+2<pParse->nBlob );
     a[1] = (szPayload >> 8) & 0xff;
     a[2] = szPayload & 0xff;
   }else{
-    assert( szType==0xe );
+    a[0] = (a[0] & 0x0f) | 0xe0;
-    assert( i+4<pParse->nBlob );
     a[1] = (szPayload >> 24) & 0xff;
     a[2] = (szPayload >> 16) & 0xff;
     a[3] = (szPayload >> 8) & 0xff;